Tufts University School of Medicine and the Indira Gandhi Government Medical College Nagpur, India, affiliated with Lata Medical Research Foundation, are proposing to expand their longstanding multidisciplinary collaboration and partnership in the study of childhood pneumonia and are applying to participate in the Global Network for Women's and Children's Health Research. The goal of this participation is to improve scientific knowledge and outcomes in neonates and young children and to expand capacity and infrastructure in the research unit at Nagpur, India. Their proposal for the Global Network application focuses on childhood pneumonia. Every year, at least 2 million children under age 5 die of pneumonia - more than the number of children who die of AIDS, malaria and measles combined. Mortality is highest in children who are hypoxemicor infected with HIV, where mortality rates are as high as 80%. Hypoxemia has long been recognized as an important predictor of mortality and poor outcome in childhood pneumonia. The World Health Organization's case-management strategy uses woefully inadequate clinical signs to detect hypoxemia, missing about 30% of children who are hypoxemic. These children do not receive much needed oxygen therapy and bear the brunt of adverse outcomes. Investment in pulse oximetry to detect hypoxemia in rural and district hospitals worldwide has not occurred, partly because no clinical trial has been conducted to determine whether access to pulse oximetry is either life-saving or cost-effective. We propose that Global Network sites conduct a cluster randomized trial to evaluate whether access to pulse oximetry and training providers in its use to guide oxygen therapy decreases treatment failure and mortality in children with pneumonia. The study will be conducted in rural hospitals that currently have no access to pulse oximetry. We will assess whether this approach is cost effective. We will also determine the microbiologic predictors of treatment failure and mortality in the eras of HIV infection and increasing antimicrobial resistance, as the etiology of pneumonia in the community setting in developing countries has not been studied since the 1980s. Introduction of pulse oximetry is a simple, easy to use, inexpensive and highly relevant technology that has the potential to improve outcomes, in a sustainable way, for one of the most pressing global health problems - childhood pneumonia.